A mounting device of this type is known from U.S. Pat. No. 4,205,473. In one embodiment disclosed in this publication, a clamping bolt with a downwardly projecting interlocking extension is respectively arranged in two mounting feet that are spaced apart from one another, so that it can be turned between a release position and a locking position. The interlocking extension is realized in the form of a truncated cone with a lateral flattening that is designed for engaging into a slot in a holding plate mounted on the weapon in the release position of the clamping bolt. When the clamping bolt is turned, the interlocking extension engages underneath the holding plate similarly to a quarter-turn fastener. The clamping bolts are rotatably guided in corresponding bores of the mounting feet with the aid of upwardly projecting pins and held in said bores by means of screws.